This invention relates to methods of forming aerosol filters and more particularly to aerosol filters which are formed with a uniform mat of a Beta fiber reinforced glass paper filter media.
Heretofore highly efficient filters have been made which are capable of retaining over 99% of particulate matter having a diameter of less than 0.3 micron with a small pressure drop in gas flow rates. However an all glass filter paper typically contains a variety of sizes of micro fibers. The relative amounts of these different sizes determines the aerosol filtration and air resistance properties. There are also quantities of coarser fibers made from chopped yarn which add mechanical strength to the sheet. An example of this chopped yarn is A-10 glass, rather coarse and stiff, they are 1/4 and 1/2 inch long and about 15 microns in diameter. Use of these large diameter stiff fibers tend to puncture the media when folding to accommodate the formation of pleated filters, and poor dispersion severely affects the mechanical strength during these forming operations.